Rapid advances in high-brightness (HB) Light Emitting Diode (LED) technology in the last 10 years have opened up the possibility of using HB-LEDs as sources of general illumination. From 1995 through 2004, the HB-LED exhibited a remarkable growth history, with an average annual growth rate of 46% to a market size of $3.7 billion in 2004. Remarkable progress of LED in external quantum efficiency, lumen output and long lifetime has initiated a market in niche lighting applications. It is believed that LEDs can have a significant share of the general lighting market in the next 10 years.
The current disadvantages of LEDs compared to conventional light sources are their much higher cost and lower lumen output per device. For increasing lumen output, high-density assembly of multiple chips in a compact module is becoming the trend. In a multi-chip assembly, the output color can also be changed dynamically as needed. As the number of chips in an array increases, interconnections among chips become very difficult and suffer from reliability. Wire bonds from chip to chip or from chip to electrical contact are typically used for interconnection. However, limited space for wiring and wire protrusion are a big challenge. The present invention introduces a means to interconnect all chips all at once without using bond wires.